Mine-jack.



0. A. MILLER.

MINE JACK.

APPLICATION FILED MAY 26, 1911.

1,009,545, I Patnted N0v, 21, 1911.

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COLUMBIA PLANOGRAPH cm, WASHINGTON. n. c.

UNITED STATES PATENT OFFICE.

CHARLES A. MILLER, 0F CONNELLSVTLLE, PENNSYLVANIA, ASSIGNOR OF ONE-HALF TO JOHN J. MALLOY, OF CONNELLSVILLE, PENNSYLVANIA.

MINE-JACK.

Specification of Letters Patent.

Patented Nov. 21, 1911.

To all whom it may concern:

Be it known that I, CHARLES A. MILLER, a citizen of the United States of America, residing at Connellsville, in the county of Fayette and State of Pennsylvania, have invented certain new and useful Improvements in Mine-Jacks, of which the following is a specification, reference being had therein to the accompanying drawing.

This invention relates to mine acks, and

the primary object of my invention is to.

A still further object of this invention is to provide a jack that is simple in construction, inexpensive to manufacture and capable of withstanding the rough usage to which mine jacks are subjected.

With the above and other objects in view the invention resides in the novel construction, combination and arrangement of parts to be hereinafter specifically described and then claimed.

Reference will now be had to the drawing, wherein Figure 1 is a perspective view of the jack, Fig. 2 is an enlarged vertical sectional view of a portion of the same, and Fig. 3 is a horizontal sectional view of the jack.

The casing or body of the jack comprises side plates 1 arranged in parallelism and having the forward edges thereof provided with extensions 2. Arranged between the plates 1 are spacing blocks 3, 4 and 5, said blocks and said plates being secured together by transversely arranged rivets or tie rods 5*. The blocks 3, 4 and 5 provide a vertical guide way 6 for a vertical rack 7 having the forward edge thereof provided with teeth 8 fronting an opening 9 formed by the blocks 4 and 5 and the extensions 2 of the plates 1. The rack 7 is of a greater length than the casing of the jack and has the up per end thereof provided with a screw threaded stem 10. Arranged upon the stem 10 and resting upon the upper end of the rack 7 is a cross-head 11 having a central smooth bore 12 to receive the stem 10. The cross-head 11 is retained upon the stem by a nut 13 or other fastening means. The outer ends of the cross-head 11 are provided with oppositely disposed angular arms 1 1.

Arranged transversely of the extensions 2 are pivot pins 15 and 16. Pivotally mounted upon the pin 15 is a dog 17 normally engaging the teeth 8 of the rack 7, said dog having the outer end thereof provided with a lip 18 to facilitate the moving of the dog out of engagement with the rack.

Pivotally mounted upon the pin 16 is a stirrup 19 and pivotally mounted in the lower end of the stirrup by a pin 20 is an eye bolt 21. Mounted upon the lower end of the eye bolt 21 and retained thereon by a nut 22 is an operating lever 23 having a toothed end 24 engaging the teeth 8 of the rack 7.

The casing of the jack is supported by a tripod, comprising legs 25 and 26. The legs 25 are connected to the plates 1 by pins 27 and these legs are retained in an angularly disposed position with the lower ends thereof flared or spread apart by metallic braces 28 secured to the plates 1, as at 29 and to the legs 25, as at 30. The leg 26 has the upper end thereof pivotally mounted between the extensions 2 by a transverse pin 31 and adjustably connected to a pivoted brace 32 by a pin 33. The brace 32 is apertured, as at 34: and the ends of said brace is pivotally mounted, by a pin 35 between the lower ends of the plates 1.

The cross-head 11 can be rotated to any desired position upon the upper end of the rack and the angle arms 1 1 are adapted to prevent the structure supported by the jack from contacting with the stem 10 and the nut 13. When the operating lever 23 is oscillated the rack 7 is intermittently elevated and held in its elevated position by the dog 17. To release the rack 7 said rack is elevated a short distance, the dog 17 swung out of engagement with the rack and then the operating lever 23. It is through the medium of the adjustable leg 26 that the jack can be positioned at any desired angle relative to the piece of work to be elevated or supported by the jack.

From the foregoing it will be observed that I have devised a portable jack which can be easily and quickly placed in position to support the roof of a mine, beams or other timbers until framing is placed in position or the sagging rooi removed.

Such changes as fall within the scope of the appended claim can be resorted to without departing from the spirit of the invention.

hat I claim is:

A jack of the type described comprising side plates, spacing blocks arranged between said plates, angularly disposed legs connected to said side plates, a leg adjustably mounted between said side plates and 00- operating with the first mentioned legs and supporting said jack in an elevated position, a rack slidably mounted between said side plates, teeth upon the side of said rack adjacent the adjust-able leg, a cross-head carried by the upper end of said rack, angle arms carried by the ends of said cross-head, a stirrup pivotally supported between said side plates, an operating lever pivotally sup ported by said stirrup and adapted to elevate said rack, and a dog pivotally supported between said side plates above said stirrup and adapted to support said rack in an ele vated position.

In testimony whereof I atfiX my signature in the presence of two witnesses.

CHARLES A. MILLER. Witnesses J H. HARSHMAN, M. E. OAKS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

